The present invention relates to an apparatus and method for cleaning vessels, such as tanks and barrels, using a pressurized fluid stream. More specifically, the present invention relates to a vessel cleaning apparatus and method that is especially well suited to cleaning vessels that cannot be contaminated with oil or other lubricants, such as a vessel used for processing sanitary products.
Vessels, such as tanks, are frequently cleaned by inserting a cleaning machine, which is supplied with heated, pressurized cleaning fluid, through a access port in the vessel. The cleaning machine ejects the cleaning fluid as a high velocity jet that scours the inside walls of the tank so as to effect a cleaning action. In order to obtain as wide a coverage as possible, such cleaning apparatus frequently employ rotating nozzles that sweep around as they eject the cleaning fluid. Cleaning apparatus sold by Gamajet Cleaning Services, Inc., assignee of the current invention, achieve almost 360xc2x0 coverage by rotating the nozzles around two mutually perpendicular axes. In such apparatus, the rotation of the nozzles is driven by a gear train that is, in turn, driven by the incoming flow of cleaning fluid via an impeller connected to the drive shaft for the gear train. Consequently, such apparatus are sometimes referred to as fluid powered, gear driven tank cleaning machines.
One early version of a fluid powered, gear driven tank cleaning machine, known commercially as the Gamajet III, is shown in U.S. Pat. No. 3,637,138 (Rucker). In the late 1980""s, Gamajet introduced the Gamajet IV cleaning machine, shown in U.S. Pat. No. 5,012,976 (Loberg), which had a relatively large maximum flow rate of 300 GPM. Like the Gamajet III, the Gamajet IV featured a gear train that comprised numerous stages of pinion and spurs gears that ultimately drove a ring gear fixed on a rotating T-housing assembly so as to cause rotation of the nozzles assembly about the first axis. A bevel gear fixed on the nozzle assembly mated with a bevel gear fixed on a stem housing, which remains stationary, so that rotation of the nozzle assembly about the first axis caused rotation of the nozzles about the second axis. The fluid inlet was formed at one end of the machine, while the gear train was disposed at the other end of the machine. The rotating nozzle assembly was disposed between the inlet and the gear train. The gear train was lubricated by the cleaning fluid flowing through the machine.
In order to enable the impeller to operate at an efficient speed without causing the nozzles to spin too quickly, which can result in the production of a mist rather than a strong jet, the gear trains of fluid powered, gear driven tank cleaning machines must be capable of high speed reduction. In both the Gamajet III and IV, this high speed reduction was achieved by means of a number of successive stages of spur and pinion gears. In each stage, a small input pinion gear turns a large output spur gear, thereby causing an incremental speed reduction. The output spur gear of that stage is connected to a small input pinon gear of the next stage, and so on. Unfortunately, this approach results in a relatively large gear train. Thus, the gear box of the Gamajet IV is over four inches in diameter. When combined with the nozzle housing, the width of the machine is about 6 inches so that the minimum entry opening for the machine is over 6inches. Consequently, such machines cannot be used in some applications, such as small tanks, which feature relatively small entry ports. Moreover, Gamajet IV machines were relatively heavy, approximately 30 lbs, making their manipulation during installation and use difficult.
In 1994, Gamajet introduced the Gamajet V tank cleaning machine, which is shown in U.S. Pat. No. 5,954,271 (Minh et al.). As a result of its configuration, the gear train of the Gamajet V is housed in a gear box having a diameter of only approximately 2 inches. This is only one-half the diameter of the Gamajet IV gearbox. As a result of the reduced size of the gear box, together with the use of a compact nozzle housing, the Gamajet V can be easily inserted into a 3 inch diameter access port. In addition, the Gamajet V is relatively light weight, weighing only about 7 lbs. The gear train of the Gamajet V featured three stages of gears rotating within a rotating cylindrical ring gear. The fiat and second stages are planetary gears, while the third stage are stationary gears. A first pinion gear, which is driven by the impeller shaft, drives the first stage of planetary gears. The first stage of planetary gears drives a second pinion gear that then drives the second stage of planetary gears. The second stage of planetary gears drives a third pinion gear that then drives the stationary third stage of gears. The stationary gears of the third stage drive the cylindrical ring gear. The cylindrical ring gear drives a pinion gear that, via idler gears, drives the ring gear that rotates the nozzle assembly. As in the Gamajet IV, the fluid inlet of the Gamajet V was formed at one end of the machine, the gear train was disposed at the other end of the machine, and the rotating nozzle assembly was disposed between the inlet and the gear train. The planetary gear train is lubricated by grease and mounted in a sealed housing to minimize contamination of the cleaning fluid by the grease. Nevertheless, gear box leakage can still occur if the seals are compromised. Still later, Gamajet developed a tank cleaning machine, which is shown in U.S. Pat. No. 6,123,271 (Delaney et al.), hereby incorporated by reference in its entirety, that located the planetary gear train between the inlet and the rotating outlet nozzles and improved the sealing of the gear train.
Despite the improvements in gear train sealing, the possibility of contamination of the cleaning fluid, and consequently the vessel being cleaned, with lubricants used within the gear train have limited the use of such cleaning machines in vessels used to process sanitary products in which lubricant contamination cannot be tolerated, such as food, beverages, pharmaceuticals, and personal care products such as shampoo. Consequently, in the past, vessels used for sanitary products that would otherwise have been ideal candidates for cleaning by compact planetary gear driven tank cleaning machines have instead been cleaned by machines that did not require gear trains and, consequently did not require lubrication, such as a non-rotating ball type cleaning apparatus, with numerous discharge nozzles formed about the circumference of a ball. However, such non-rotating apparatus cannot clean as effectively as the planetary gear train driven cleaning machines discussed above.
Consequently, it would be desirable developed a planetary gear driven tank cleaning machine that did not require the use of any lubricants, including lubricants in the planetary gear train, that might contaminate the cleaning fluid.
It is an object of the current invention to provide an improved cleaning machine for cleaning the inside of vessels. This and other objects are achieved in an apparatus for cleaning the interior of a vessel by ejecting a rotating stream of cleaning fluid, comprising (i) a first fluid inlet for receiving the cleaning fluid, (ii) a rotatable housing mounted for rotation about a first axis, (iii) a nozzle having a first fluid outlet for ejecting the cleaning fluid received by the first fluid inlet, the nozzle rotatably mounted on the rotatable housing so that the nozzle rotates about a second axis, a first fluid passage placing the first fluid inlet in fluid flow communication with the first fluid outlet, (iv) an input shaft driven by the fluid received by the first fluid inlet, (v) a planetary gear train comprising a sun gear and at least one planetary gear mounted for rotation about the sun gear, the planetary gear train driven by the input shaft, the planetary gear train driving the rotatable housing to rotate about the first axis, (vi) a housing at least partially enclosing the planetary gear train, a second fluid passage formed within the housing, the sun gear and the planetary gear disposed within the second fluid passage, the second fluid passage having a second fluid inlet and a second fluid outlet that together place the second fluid passage in flow communication with the first fluid passage, wherein at least a portion of the cleaning fluid received by the first fluid inlet flows through a portion of the first fluid passage and then flows into the second fluid inlet and then flows through the second fluid passage so as to flow over the sun gear and the planetary gear and then flows through the second fluid outlet so as to reenter the first fluid passage and then flows through the first fluid outlet.
The current invention also encompasses a method of cleaning a vessel suitable for containing a sanitary product, comprising the steps of (i) introducing a cleaning machine into the vessel, (ii) introducing a flow of cleaning fluid into an inlet of the cleaning machine, (iii) rotating an impeller by directing the cleaning fluid to flow over the impeller so that the impeller drives rotation of a planetary gear train, the planetary gear train driving rotation of a rotatable body housing about a first axis, the rotatable body housing driving rotation of a rotatable nozzle housing about a second axis, (v) directing the flow of cleaning fluid received by the inlet through a passage to a nozzle mounted on the rotatable nozzle housing so that the nozzle rotates with the rotatable nozzle housing, (vi) ejecting the cleaning fluid from the nozzle, (vii) cooling and lubricating the planetary gear train by diverting a portion of the flow of cleaning fluid from the passage so as to cause the portion of the cleaning fluid to flow through the planetary gear train and then reintroducing the portion of the cleaning fluid back into the passage so that the reintroduced portion of the cleaning fluid is then ejected from the nozzle.